Acacia armitii F.Muell. ex Maiden, J. & Proc. Roy. Soc. New South Wales 51: 84 (1917)
Shrub or slender tree to 7.5 m high. Branchlets prominently angled, fawn or yellowish, glabrous, resinous. Phyllodes erect, very narrowly elliptic to almost linear, flat, straight or very slightly curved, 4.5–17 cm long, 3.5–17 mm wide, thinly coriaceous to coriaceous, yellow-green, ciliolate to glabrous, resinous, the main veins yellowish, with prominent midvein and 1 subprominent vein either side, with 4–8 minor parallel, rarely anastomosing veins per mm; gland basal, elliptic, c. 1 mm long. Peduncles glabrous or sparsely hairy. Spikes solitary, axillary. Flowers 5-merous; calyx 0.6–0.8 mm long, the sepals free, 0.05–0.1 mm wide, with rounded apices, pubescent; corolla 1.2–1.6 mm long, dissected to 2/5, the lower half pubescent especially on midrib; ovary pubescent. Pods erect, linear, straight-sided or very slightly constricted between seeds, undulate, straight, 2.7–5.5 cm long, 3.4–4.7 mm wide, yellowish brown, sparsely pubescent especially along margins, very resinous when young; margins prominent. Seeds 5–10, slightly oblique to longitudinal, broadly oblong to broadly elliptic, depressed dorso-ventrally, 2–3.2 mm long, blackish brown, the areole slightly paler, closed, with pale halo around pleurogram; funicle folded 2 or 3 times, cream-coloured.
Only known from the Einasleigh R. area in central-northern Qld and on a sandstone plateau S of Goomadeer, as well as Coopers Ck at Nabarlek, N.T.; locally common in sandy or shallow, rocky soils, on creek banks and river flats. Flowers recorded July & Sept., fide G.J.Leach, Nuytsia 9: 362 (1994). Fruiting Aug.–Oct.
Acacia armitii differs from A. plectocarpa subsp. plectocarpa by having yellowish, more prominently angled stems, and narrower pods with smaller seeds. The seeds of the latter species are also often rotund to orbicular in outline. Acacia plectocarpa subsp. tanumbirinensis has narrower and usually longer phyllodes, while A. echinuliflora has narrower flower-spikes and wider pods than A. armitii . Acacia echinuliflora is also distinguished by having petals invested with an indumentum of dense, patent, yellow hairs, fide G.J.Leach, Nuytsia 9: 357 (1994). Without pods specimens of these species can be confused with A. torulosa , which differs mostly in having longer, moniliform, longitudinally wrinkled-ridged pods. Acacia torulosa is also more widespread than A . armitii and A. echinuliflora , and has branchlets soon becoming less angular to terete, unlike the more sharply angular ultimate branchlets of the latter two species.
Type of accepted name
Einasleigh R., Qld, W.Armit 1014 ; holo: NSW; iso: MEL, PERTH (fragment & photo).
Racosperma armitii (F.Muell. ex Maiden) Pedley, Austrobaileya 2: 345 (1987). Type: as for accepted name.
[ Acacia delibrata auct. non A.Cunn. ex Benth.: F.Mueller, Iconogr. Austral. Acacia dec. 11 [pl. 1] (1888)]
G.J.Leach, Nuytsia 9: 357, fig. 4 & 361, fig. 5 (1994).
N.T.: Upper Goomadeer R. area, C.R.Dunlop 7228 & P.F.Munns (BRI, DNA, NSW, PERTH); Nabarlek, Coopers Ck, R.Hinz 596 (DNA, PERTH); 1236’S, 13319’E, M.Lazarides 7572 (NSW). Qld: c. 10 km S of the Einasleigh–Forsayth road on track leading to Robinhood Stn, J.R.Clarkson 2576 & N.B.Byrnes (BRI).